Doubles player Renata Voracova, who was deported from Australia after her visa was cancelled, did "nothing wrong", says the Women's Tennis Association.
The 38-year-old Czech was allowed to enter the country after presenting a Covid vaccination exemption and played in a tournament in Melbourne.
However, she was subsequently detained and left Australia on Saturday.
"The complications experienced over the past few days... are unfortunate," said the WTA.
"Renata Voracova followed these rules and procedures, was cleared for entry upon her arrival, competed in an event and then suddenly had her visa cancelled when she had done nothing wrong.
"We will continue to work with all authorities on addressing this unfortunate situation in an appropriate manner."
Men's world number one Novak Djokovic is hoping to remain in Australia and defend his Australian Open title after his visa was similarly revoked before a judge overturned that decision on Monday.
Voracova, who intends to pursue compensation from Tennis Australia, told BBC Radio 5 Live on Tuesday that she was subject to six hours of questioning by immigration officials before being put on a flight back to the Czech Republic.
She added that she had intended to be vaccinated against Covid but suffered medical complications after contracting the virus that prevented her getting the jab.
The WTA said, despite its concerns over Voracova's case, it believed "all players should be vaccinated" and it was "in full support of the immigration policies that have been put in place" in Australia for the early part of the 2022 season.